U.S. patent application number 17/263948 was filed with the patent office on 2021-07-29 for vehicle position processing apparatus, vehicle control apparatus, vehicle position processing method, and vehicle control method.
This patent application is currently assigned to Mitsubishi Electric Corporation. The applicant listed for this patent is Mitsubishi Electric Corporation. Invention is credited to Masaya ENDO, Yasuyoshi HORI, Kunio UEDA, Takahiro URABE.
Application Number | 20210229741 17/263948 |
Document ID | / |
Family ID | 1000005569459 |
Filed Date | 2021-07-29 |
United States Patent
Application |
20210229741 |
Kind Code |
A1 |
URABE; Takahiro ; et
al. |
July 29, 2021 |
VEHICLE POSITION PROCESSING APPARATUS, VEHICLE CONTROL APPARATUS,
VEHICLE POSITION PROCESSING METHOD, AND VEHICLE CONTROL METHOD
Abstract
To provide a vehicle position processing apparatus, a vehicle
control apparatus, a vehicle position processing method, and a
vehicle control method capable of increasing the number of the
position information of front object used for generation of the
trajectory and improving the generation accuracy of the trajectory.
A vehicle position processing apparatus, a vehicle control
apparatus, a vehicle position processing method, and a vehicle
control method that obtains positions of a target object, sets a
trajectory generation range which is a continuous range including a
position of the target object close to a position of the present
own vehicle, selects positions of the target object included in the
trajectory generation range among the plural positions of the
target object, as target object positions for trajectory
generation, and generates a trajectory of the target object based
on the target object positions for trajectory generation.
Inventors: |
URABE; Takahiro; (Tokyo,
JP) ; ENDO; Masaya; (Tokyo, JP) ; HORI;
Yasuyoshi; (Tokyo, JP) ; UEDA; Kunio; (Tokyo,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Mitsubishi Electric Corporation |
Tokyo |
|
JP |
|
|
Assignee: |
Mitsubishi Electric
Corporation
Tokyo
JP
|
Family ID: |
1000005569459 |
Appl. No.: |
17/263948 |
Filed: |
September 20, 2018 |
PCT Filed: |
September 20, 2018 |
PCT NO: |
PCT/JP2018/034762 |
371 Date: |
January 28, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60W 2554/4041 20200201;
B60W 30/10 20130101; G01C 21/3407 20130101; B62D 15/02 20130101;
B60W 40/04 20130101 |
International
Class: |
B62D 15/02 20060101
B62D015/02; G01C 21/34 20060101 G01C021/34; B60W 30/10 20060101
B60W030/10; B60W 40/04 20060101 B60W040/04 |
Claims
1. A vehicle position processing apparatus comprising at least one
processor configured to implement: a target object position
acquisitor that obtains positions of a target object; a data
selector for trajectory generation that sets a trajectory
generation range which is a continuous range including a position
of the target object close to a position of a present own vehicle,
and selects positions of the target object included in the
trajectory generation range among plural positions of the target
object, as target object positions for trajectory generation; and a
trajectory generator that generates a trajectory of the target
object based on the target object positions for trajectory
generation.
2. The vehicle position processing apparatus according to claim 1,
wherein the data selector for trajectory generation sets the
trajectory generation range to a continuous range, which includes
position of the target object close to a position of front and back
direction of the present own vehicle and in which an absolute value
of angle of change direction of positions of the target object with
respect to the front and back direction of the present own vehicle
becomes smaller than a determination angle.
3. The vehicle position processing apparatus according to claim 1,
wherein the data selector for trajectory generation determines
front side positions of the target object, which are located on
front side of the present own vehicle, among the plural positions
of the target object, calculates a change direction of positions of
the target object in a first direction, about each of the front
side positions of the target object, determines a position where an
absolute value of angle of the change direction of positions of the
target object with respect to a front direction becomes greater
than or equal to a determination angle, among the front side
positions of the target object, and selects positions located on a
second direction side of the determined position among the front
side positions of the target object, as the target object positions
for trajectory generation, wherein the first direction is an order
of positions in which the front side positions of the target object
changes in the front side, at least at the front side position of
the target object close to the position of the present own vehicle,
and wherein the second direction is an order of positions opposite
to the first direction.
4. The vehicle position processing apparatus according to claim 3,
wherein the data selector for trajectory generation determines back
side positions of the target object, which are located on a back
side of the present own vehicle, among the plural positions of the
target object, calculates a change direction of positions of the
target object in the second direction, about each of the back side
positions of the target object, determines a position where an
absolute value of angle of the change direction of positions of the
target object with respect to a back direction becomes greater than
or equal to the determination angle, among the back side positions
of the target object, and further selects positions located on the
first direction side of the determined position among the back side
positions of the target object, as the target object positions for
trajectory generation.
5. The vehicle position processing apparatus according to claim 1,
Wherein the data selector for trajectory generation determines
front side positions of the target object, which are located on
front side of the present own vehicle, among the plural positions
of the target object, determines a position where the positions of
the target object changes in a back direction in a first direction,
among the front side positions of the target object, and selects
positions located on a second direction side of the determined
position among the front side positions of the target object, as
the target object positions for trajectory generation, wherein the
first direction is an order of positions in which the front side
positions of the target object changes in the front side, at least
between front and back positions of the front side position of the
target object close to the position of the present own vehicle, and
wherein the second direction is an order of positions opposite to
the first direction.
6. The vehicle position processing apparatus according to claim 5,
Wherein the data selector for trajectory generation determines back
side positions of the target object, which are located on a back
side of the present own vehicle, among the plural positions of the
target object, determines a position where the positions of the
target object changes in a back direction in the second direction,
among the back side positions of the target object, and further
selects positions located on the first direction side of the
determined position among the back side positions of the target
object, as the target object positions for trajectory
generation.
7. The vehicle position processing apparatus according to claim 1,
wherein the target object position acquisitor is provided with a
front object position acquisitor that obtains a relative position,
with respect to the own vehicle, of a front object which exists in
front of the own vehicle, an own position information acquisitor
that obtains moving information of the own vehicle, and a history
position calculator that, based on the relative positions and the
moving informations of the own vehicle obtained at plural time
points of present and past, calculates history positions of the
front object of the plural time points on a basis of the position
of the present own vehicle, as the plural positions of the target
object.
8. The vehicle position processing apparatus according to claim 1,
wherein the target object position acquisitor is provided with an
own position information acquisitor that obtains the position of
the present own vehicle, and a road position acquisitor that
obtains positions of plural road points arranged in order along a
traveling direction of a road where the own vehicle travels, from
map data, based on the position of the present own vehicle, as the
plural positions of the target object.
9. The vehicle position processing apparatus according to claim 1,
wherein the target object position acquisitor calculates, as the
position of the target object, a coordinate position of the target
object on an own vehicle coordinate system which is a coordinate
system with two coordinate axes of front direction and lateral
direction of the present own vehicle, and wherein the trajectory
generator generates the trajectory on the own vehicle coordinate
system.
10. The vehicle position processing apparatus according to claim 9,
wherein the trajectory generator generates the trajectory by
approximation using a polynomial in which a value of the coordinate
axis of front direction is input variable, and a value of the
coordinate axis of lateral direction is output variable.
11. A vehicle control apparatus comprising: the vehicle position
processing apparatus according to claim 1, and a steering
controller that performs a trajectory tracking steering control
which controls a steering angle of the own vehicle so that the own
vehicle follows the trajectory.
12. The vehicle control apparatus according to claim 11, wherein
the steering controller sets a position of the trajectory which is
located ahead by a front gaze distance from the position of the
present own vehicle, to a target position of the lateral direction
of the own vehicle, controls the steering angle so that a position
of the lateral direction of the own vehicle approaches the target
position, and sets the front gaze distance, to a distance shorter
than a front distance from the position of the present own vehicle
to a front endpoint of the trajectory.
13. The vehicle control apparatus according to claim 11, wherein
the steering controller performs the trajectory tracking steering
control, when the front distance from the position of the present
own vehicle to the front endpoint of the trajectory is greater than
or equal to a lower limit value, and does not perform the
trajectory tracking steering control, when the front distance is
smaller than the lower limit value.
14. The vehicle control apparatus according to claim 11, wherein
the trajectory generator generates the trajectory by approximation
using a polynomial, and wherein the steering controller performs
the trajectory tracking steering control, when number of the target
object positions for trajectory generation is greater than or equal
to a value obtained by adding 1 to a maximum order of the
polynomial, and does not perform the trajectory tracking steering
control, when the number of the target object positions for
trajectory generation is smaller than the value obtained by adding
1 to the maximum order.
15. A vehicle position processing method comprising: a target
object position acquiring that obtains positions of a target
object; a data selecting for trajectory generation that sets a
trajectory generation range which is a continuous range including a
position of the target object close to a position of a present own
vehicle, and selects positions of the target object included in the
trajectory generation range among plural positions of the target
object, as target object positions for trajectory generation; and a
trajectory generating that generates a trajectory of the target
object based on the target object positions for trajectory
generation.
16. A vehicle control method comprising: the vehicle position
processing method according to claim 15, and a steering controlling
that performs a trajectory tracking steering control which controls
a steering angle of the own vehicle so that the own vehicle follows
the trajectory.
Description
TECHNICAL FIELD
[0001] Present disclosure is related with a vehicle position
processing apparatus, a vehicle control apparatus, a vehicle
position processing method, and a vehicle control method.
BACKGROUND ART
[0002] As a prior art, there is a technology disclosed in PLT 1. In
the technology of PLT 1, the position of the preceding vehicle is
obtained in the predetermined period, and the current position of
the own vehicle is obtained. Then, in the technology of PLT 1, the
current position of the own vehicle is set to the reference point,
the detection position of the preceding vehicle corresponding to
the position ahead by the first distance from the current position
of the own vehicle is set to the front point, and the detection
position of the preceding vehicle corresponding to the position
behind by the second distance is set to the back point. Then, in
the technology of PLT 1, by the line of the same curvature which
connects the set reference point, the front point, and the back
point, the target traveling route which the own vehicle travels is
set.
[0003] At that time, in the technology of PLT 1, when the detection
position of the preceding vehicle does not exist ahead by the first
distance, the front point is changed to the detection position of
the preceding vehicle of different distance from the first
distance. Then, when the front point is changed, the reference
point is changed to the front and back direction with respect to
the current position of the own vehicle so that the distance from
the reference point to the changed front point and the distance
from the reference point to the back point become a predetermined
ratio.
CITATION LIST
Patent Literature
[0004] PLT 1: JP 2017-52412 A
SUMMARY OF INVENTION
Technical Problem
[0005] However, in the technology of PLT 1, since the target
traveling route is generated only by the reference point, the front
point, and the back point, the detection positions of the preceding
vehicle other than these front point and back point are not
considered. Therefore, an error occurs between the traveling
trajectory of the preceding vehicle, and the set target traveling
route. Especially when the preceding vehicle is traveling on the
sharp curve, an error becomes large due to occurrence of shortcut
and the like.
[0006] Thus, it is desired to provide a vehicle position processing
apparatus, a vehicle control apparatus, a vehicle position
processing method, and a vehicle control method capable of
increasing the number of the position information of the target
object used for generation of the trajectory and improving the
generation accuracy of the trajectory.
Solution to Problem
[0007] A vehicle position processing apparatus according to the
present disclosure including:
[0008] a target object position acquisition unit that obtains
positions of a target object;
[0009] a data selection unit for trajectory generation that sets a
trajectory generation range which is a continuous range including a
position of the target object close to a position of a present own
vehicle, and selects positions of the target object included in the
trajectory generation range among plural positions of the target
object, as target object positions for trajectory generation;
and
[0010] a trajectory generation unit that generates a trajectory of
the target object based on the target object positions for
trajectory generation.
[0011] A vehicle control apparatus according to the present
disclosure including:
[0012] the above vehicle position processing apparatus, and
[0013] a steering control unit that performs a trajectory tracking
steering control which controls a steering angle of the own vehicle
so that the own vehicle follows the trajectory.
[0014] A vehicle position processing method according to the
present disclosure including:
[0015] a target object position acquisition step that obtains
positions of a target object;
[0016] a data selection step for trajectory generation that sets a
trajectory generation range which is a continuous range including a
position of the target object close to a position of a present own
vehicle, and selects positions of the target object included in the
trajectory generation range among plural positions of the target
object, as target object positions for trajectory generation;
and
[0017] a trajectory generation step that generates a trajectory of
the target object based on the target object positions for
trajectory generation.
[0018] A vehicle control method according to the present disclosure
including:
[0019] the above steps of the vehicle position processing method,
and
[0020] a steering control step that performs a trajectory tracking
steering control which controls a steering angle of the own vehicle
so that the own vehicle follows the trajectory.
Advantage of Invention
[0021] According to the vehicle position processing apparatus and
the vehicle position processing method of the present disclosure,
based on the positions of the target object included in the
trajectory generation range which is the continuous range including
the position of the target object close to the position of the
front and back direction of the present own vehicle, the trajectory
of the target object can be generated. Therefore, number of the
positions of the target object used for generation of the
trajectory can be increased, and the generation accuracy of the
trajectory can be improved. According to the vehicle control
apparatus and the vehicle control method of the present disclosure,
since the trajectory generated with good accuracy is used, the
tracking accuracy to the target object can be improved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a schematic block diagram of the vehicle position
processing apparatus according to Embodiment 1;
[0023] FIG. 2 is a schematic hardware configuration diagram of the
vehicle position processing apparatus according to Embodiment
1;
[0024] FIG. 3 is a schematic flowchart for explaining the
processing of the vehicle position processing apparatus according
to Embodiment 1;
[0025] FIG. 4 is a figure for explaining the relative position of
the front object on the own vehicle coordinate system according to
Embodiment 1;
[0026] FIG. 5 is a figure for explaining data stored in the storage
apparatus, by correlating with the each number of detection time
point according to Embodiment 1;
[0027] FIG. 6 is a figure for explaining calculation of the moving
information of the own vehicle between numbers of detection time
points according to Embodiment 1;
[0028] FIG. 7 is a figure for explaining change of the history
positions of the front object by moving of the own vehicle
according to Embodiment 1;
[0029] FIG. 8 is a flowchart for explaining the setting processing
of the trajectory generation range of front side according to
Embodiment 1;
[0030] FIG. 9 is a figure for explaining calculation of the change
angle of the history positions of the front side according to
Embodiment 1;
[0031] FIG. 10 is a figure for explaining the behavior of the
setting processing of the trajectory generation range of the front
side according to Embodiment 1;
[0032] FIG. 11 is a flowchart for explaining the setting processing
of the trajectory generation range of the back side according to
Embodiment 1;
[0033] FIG. 12 is a figure for explaining calculation of the change
angle of the history positions of the back side according to
Embodiment 1;
[0034] FIG. 13 is a figure for explaining the behavior of the
setting processing of the trajectory generation range of the back
side according to Embodiment 1;
[0035] FIG. 14 is a figure for explaining the trajectory generation
according to the comparative example;
[0036] FIG. 15 is a figure for explaining the trajectory generation
according to Embodiment 1;
[0037] FIG. 16 is a figure for explaining setting of the target
position in the trajectory tracking steering control according to
Embodiment 1;
[0038] FIG. 17 is a figure for explaining setting of the map data
of the front gaze distance according to Embodiment 1;
[0039] FIG. 18 is a flowchart for explaining the setting processing
of the trajectory generation range of front side according to
Embodiment 2;
[0040] FIG. 19 is a figure for explaining the behavior of the
setting processing of the trajectory generation range of the front
side according to Embodiment 2;
[0041] FIG. 20 is a flowchart for explaining the setting processing
of the trajectory generation range of the back side according to
Embodiment 2;
[0042] FIG. 21 is a figure for explaining the behavior of the
setting processing of the trajectory generation range of the back
side according to Embodiment 2;
[0043] FIG. 22 is a schematic block diagram of the vehicle position
processing apparatus according to Embodiment 3; and
[0044] FIG. 23 is a figure for explaining the trajectory generation
range according to Embodiment 3.
DETAILED DESCRIPTION OF THE EMBODIMENTS
1. Embodiment 1
[0045] A vehicle position processing apparatus 10 (a vehicle
control apparatus) according to Embodiment 1 will be explained with
reference to drawings. FIG. 1 is a schematic block diagram of the
vehicle position processing apparatus 10 (the vehicle control
apparatus) according to the present embodiment.
[0046] In the present embodiment, the vehicle position processing
apparatus 10 is mounted on an own vehicle. The vehicle position
processing apparatus 10 is provided with processing units such as a
target object position acquisition unit 11, a data selection unit
12 for trajectory generation, a trajectory generation unit 13, and
a steering control unit 14. Each processing of the vehicle position
processing apparatus 10 is realized by processing circuits provided
in the vehicle position processing apparatus 10. As shown in FIG.
2, specifically, the vehicle position processing apparatus 10 is
provided with an arithmetic processor 90 such as CPU (Central
Processing Unit), storage apparatuses 91, an input and output
circuit 92 which outputs and inputs external signals to the
arithmetic processors 90, and the like.
[0047] As the arithmetic processor 90, ASIC (Application Specific
Integrated Circuit), IC (Integrated Circuit), DSP (Digital Signal
Processor), FPGA (Field Programmable Gate Array), various kinds of
logical circuits, various kinds of signal processing circuits, and
the like may be provided. As the arithmetic processor 90, a
plurality of the same type ones or the different type ones may be
provided, and each processing may be shared and executed. As the
storage apparatuses 91, there are provided a RAM (Random Access
Memory) which can read data and write data from the arithmetic
processor 90, a ROM (Read Only Memory) which can read data from the
arithmetic processor 90, and the like. As the storage apparatuses
91, various kinds of storage apparatus, such as a flash memory,
EEPROM (Electrically Erasable Programmable Read Only Memory), a
hard disk, and a DVD apparatus may be used.
[0048] The input and output circuit 92 is provided with an A/D
converter, an input port, a driving circuit, an output port, a
communication device, and the like. The input and output circuit 92
is connected with a front body detecting device 20, an own position
detecting device 21, and the like, and inputs these output signals
into the arithmetic processor 90. The input and output circuit 92
is connected to the steering apparatus 24 and the like, and outputs
the output signal of the arithmetic processor 90 to this
device.
[0049] Then, the arithmetic processor 90 runs software items
(programs) stored in the storage apparatus 91 such as a ROM and
collaborates with other hardware devices in the vehicle position
processing apparatus 10, such as the storage apparatus 91, and the
input and output circuit 92, so that the respective functions of
the processing units 11 to 14 included in the vehicle position
processing apparatus 10 are realized. Setting data items such as
determination angle, map data to be utilized in the processing
units 11 to 14 are stored, as part of software items (programs), in
the storage apparatus 91 such as a ROM. Each function of the
vehicle position processing apparatus 10 will be described in
detail below.
[0050] FIG. 3 is a schematic flowchart for explaining procedure (a
vehicle position processing method, a vehicle control method) of
processing of the vehicle position processing apparatus 10
according to the present embodiment. The processing of the
flowchart in FIG. 3 is recurrently executed every predetermined
operation cycle by the arithmetic processor 90 executing software
(a program) stored in the storage apparatus 91.
1-1. Target Object Position Acquisition Unit 11
[0051] In the step S01 of FIG. 3, the target object position
acquisition unit 11 performs a target object position acquisition
processing (a target object position acquisition step) that obtains
positions of a target object. In the present embodiment, the target
object position acquisition unit 11 obtains plural positions of the
target object arranged in order. As explained below, the target
object is a front object. The plural positions of the target object
arranged in order are plural history positions of the front object
arranged in detection order (order of number of detection time
point, time series order). And as number of order, the number of
detection time point is set. As shown in FIG. 1, the target object
position acquisition unit 11 is provided with an own position
information acquisition unit 11a, a front object position
acquisition unit 11b, and a history position calculation unit
11c.
1-1-1. Front Object Position Acquisition Unit 11b
[0052] The front object position acquisition unit 11b obtains a
relative position, with respect to the own vehicle, of the front
object which exists in front of the own vehicle. In the present
embodiment, the front object position acquisition unit 11b obtains
the relative position of the front object based on the output
signal of the front body detecting device 20.
[0053] The front body detecting device 20 is a device which detects
a body existing in front of the own vehicle. As the front body
detecting device 20, for example, one or more of various kinds of
detecting devices, such as a monitoring camera, a millimeter wave
radar, LIDAR (Light Detection and Ranging), and an ultrasonic
sensor are used. In the case where the monitoring camera is used,
by performing various kinds of well-known image processing to the
picture in front of the own vehicle imaged by the camera, a body,
such as a preceding vehicle which exists in front of the own
vehicle, is detected, and the relative position of the detected
body with respect to the own vehicle is detected. In the case where
the millimeter wave radar, LIDAR, or the ultrasonic sensor is used,
a millimeter wave, a laser, or an ultrasonic wave is irradiated to
front of the own vehicle, and the relative position of the detected
body with respect to the own vehicle is detected, based on a
irradiation direction, and a time difference until receiving a
reflected wave reflected by the body, such as the preceding vehicle
which exists in front.
[0054] The front object position acquisition unit 11b obtains the
relative position of the front object for every detection period.
The detection period may be variable according to driving
condition, such as speed of the own vehicle, or may be a
preliminarily set fixed value.
[0055] From the front bodies detected by the front body detecting
device 20, the front object position acquisition unit 11b sets the
preceding vehicle which is traveling in front of the own vehicle,
to the front object continuously. For example, the front object
position acquisition unit 11b detects bodies whose the detection
position and the detection feature are close between numbers of
detection time point, as the same front object, and detects the
relative position of the same front object in the detection period
continuously. When a plurality of preceding vehicles are detected,
processing of generating a trajectory about each the preceding
vehicle is performed, and a trajectory for performing a trajectory
tracking steering control is selected from the plurality of
trajectories. In the following, the case where the one same
preceding vehicle is continuously set as the front object is
explained as an example.
[0056] As shown in FIG. 4, the front object position acquisition
unit 11b calculates relative position coordinates (Xf, Yf) of the
front object (in this example, the preceding vehicle) with respect
to the own vehicle, on a coordinate system (hereinafter, referred
to as an own vehicle coordinate system) where the front direction
and the lateral direction of the present own vehicle are set as two
coordinate axes X and Y. The front direction (also called as a
traveling direction) of the own vehicle is set as the X-axis, and
the lateral direction (in this example, left) of the own vehicle
orthogonal to the front direction is set as the Y-axis. The own
vehicle is located at zero point of the X-axis and the Y-axis. As
shown in FIG. 5, the front object position acquisition unit 11b
stores the relative position coordinates (Xf.sub.i, Yf.sub.i) of
the front object detected at the number i of detection time point
to the rewritable storage apparatus 91 such as RAM of the vehicle
position processing apparatus 10, by correlating with the number i
of detection time point. The data of the numbers of detection time
point which are older than the present by a predetermined period is
erased from the storage apparatus 91, in order to reduce data
volume.
1-1-2. Own Position Information Acquisition Unit 11a
[0057] The own position information acquisition unit 11a obtains
moving information of the own vehicle. In the present embodiment,
the own position information acquisition unit 11a obtains the
moving information of the own vehicle based on the output signal of
the own position detecting device 21.
[0058] The own position detecting device 21 is a device which
detects the moving information of the own vehicle. As the own
position detecting device 21, for example, one or more of various
kinds of detecting devices, such as an acceleration sensor, a GPS
(Global Positioning System) receiver, and an azimuth sensor are
used. The own position detecting device 21 may be provided inside
of the vehicle position processing apparatus 10, or may be provided
outside of the vehicle position processing apparatus 10.
[0059] The own position information acquisition unit 11a obtains
the moving information of the own vehicle for every detection
period. The own position information acquisition unit 11a
calculates the moving information of the own vehicle between
numbers of detection time point. For example, the own position
information acquisition unit 11a calculates moving information
(parallel moving and rotation) of the own vehicle coordinate system
between numbers of detection time point, as the moving information.
In the present embodiment, as shown in FIG. 6, the own position
information acquisition unit 11a calculates a moving position
(.DELTA.X0.sub.i0, .DELTA.Y0.sub.i0) and a rotational angle
.theta..sub.i0 of the own vehicle coordinate system of this time
number i.sub.0 of detection time point, on the basis of the own
vehicle coordinate system of the last time number i.sub.0-1 of
detection time point.
1-1-3. History Position Calculation Unit 11c
[0060] The history position calculation unit 11c calculates history
positions of the front object of the plural time points on the
basis of the position of the present own vehicle, based on the
relative positions of the front object and the moving informations
of the own vehicle which were obtained at plural time points of
present and past. The history positions of the front object of
plural time points correspond to the plural positions of the target
object. This history positions are positions where the relative
positions of the front object detected on the basis of the position
of the own vehicle of that time point at respective plural time
points are converted into the relative positions on the basis of
the position of the present own vehicle.
[0061] As shown in FIG. 7, when the own vehicle moves, the relative
position of the past front object viewed on the basis of the
position of the present own vehicle (the own vehicle coordinate
system) moves to a direction opposite to the moving direction of
the own vehicle by moving amount of the own vehicle, and rotates to
a direction opposite to the rotation direction of the own vehicle
by rotational angle of the own vehicle.
[0062] Then, for every detection period, the history position
calculation unit 11c performs an affine transformation that moves
and rotates the history positions (Xfh.sub.i, Yfh.sub.i)
corresponding to the relative positions detected at respective
numbers i of detection time point (i= . . . , i.sub.0-2,
i.sub.0-1), to a direction opposite to the moving amount
(.DELTA.X0.sub.i0, .DELTA.Y0.sub.i0) and the rotational angle
.theta..sub.i0 of the own vehicle coordinate system which is
detected at this time number i.sub.0 of detection time point,
respectively, and updates the history positions (Xfh.sub.i,
Yfh.sub.i) corresponding to the relative positions detected at
respective numbers of detection time point. For every detection
period, the history position calculation unit 11 performs
cumulatively the affine transformation that reflects moving of the
own vehicle between periods on the history positions of respective
detection time points, and updates the history positions of
respective detection time points.
1-2. Data Selection Unit 12 for Trajectory Generation
[0063] In the step S02 of FIG. 3, the data selection unit 12 for
trajectory generation performs a data selection processing for
trajectory generation (a data selection step for trajectory
generation) that sets a trajectory generation range which is a
continuous range including a position of the target object close to
a position of the present own vehicle, and selects positions of the
target object included in the trajectory generation range among the
plural positions of the target object, as target object positions
for trajectory generation. In the present embodiment, the position
of the target object is managed by the number. The data selection
unit 12 for trajectory generation sets the trajectory generation
range which is a range of continuous numbers of order including the
number of the position of the target object close to the position
of the present own vehicle, and selects positions of the target
object included in the trajectory generation range among the plural
positions of the target objects, as the target object positions for
trajectory generation. The position of the target object close to
the position of the present own vehicle becomes a position of the
target object closest to the position of the present own vehicle,
among positions of the target object which are located on the front
side of the present own vehicle.
[0064] And, in the present embodiment, the data selection unit 12
for trajectory generation sets the trajectory generation range
which is a range of continuous numbers of detection time point
including the number of detection time point of the history
position close to the position of the front and back direction of
the present own vehicle, and selects history positions included in
the trajectory generation range among the history positions of
plural time points, as the target object positions for trajectory
generation.
[0065] According to this configuration, based on the history
positions included in the trajectory generation range which is the
range of the continuous numbers of detection time point including
the history position of the front object close to the position of
the front and back direction of the present own vehicle, the
trajectory of the target object can be generated. Therefore, number
of the history positions of the front object used for generation of
the trajectory can be increased, and the generation accuracy of the
trajectory can be improved.
[0066] The data selection unit 12 for trajectory generation sets
the trajectory generation range to a continuous range, which
includes position of the target object close to a position of front
and back direction of the present own vehicle and in which an
absolute value of angle of change direction of positions of the
target object with respect to the front and back direction of the
present own vehicle becomes smaller than a determination angle.
[0067] In the present embodiment, the data selection unit 12 for
trajectory generation sets the trajectory generation range to a
range of continuous numbers of detection time point which include
the number of the history position close to the position of the
front and back direction of the present own vehicle and in which an
absolute value of angle of change direction of the history
positions between numbers of detection time point with respect to
the front and back direction of the present own vehicle becomes
smaller than the determination angle .alpha.j.
[0068] According to this configuration, inclination of the change
direction of the history positions of the front object with respect
to the front and back direction of the present own vehicle can be
made smaller than the determination angle .alpha.j continuously to
the front and back direction from the position of the front and
back direction of the present own vehicle. If the inclination of
the change direction of the history positions becomes large too
much, there is a possibility that an approximate precision of the
trajectory described below may be deteriorated. Therefore, by
excluding the history positions where the inclination becomes
larger than the determination angle .alpha.j, it is possible to
suppress deterioration of the approximate precision of the
trajectory. As described later, in the case of performing a
trajectory tracking steering control which makes the own vehicle
follow the trajectory, when inclination of the trajectory becomes
large too much, tracking of the own vehicle becomes not easy.
Therefore, by excluding the history positions where the inclination
becomes larger than the determination angle .alpha.j, the
trajectory that the own vehicle can follow can be generated.
[0069] For example, the determination angle .alpha.j is set to an
angle less than or equal to .pi./2 (90 degrees). The data selection
unit 12 for trajectory generation may change the determination
angle .alpha.j according to the detection period, the speed of the
own vehicle, and the like. For example, the determination angle
.alpha.j is decreased as the detection period becomes short, and
the determination angle .alpha.j is decreased as the speed of the
own vehicle becomes high.
[0070] In the present embodiment, the data selection unit 12 for
trajectory generation divides the history positions of plural time
points into front side and back side of the position of the present
own vehicle, and selects the history positions for trajectory
generation about each of the front side history positions and the
back side history positions.
<Processing of Front Side>
[0071] Processing of the front side will be explained. The data
selection unit 12 for trajectory generation determines front side
positions of the target object, which are located on the front side
of the present own vehicle, among the plural positions of the
target object. The data selection unit 12 for trajectory generation
calculates a change direction of positions of the target object in
a first direction, about each of the front side positions of the
target object, and determines a position where an absolute value of
angle of the change direction of positions of the target object
with respect to the front direction becomes greater than or equal
to the determination angle .alpha.j, among the front side positions
of the target object. The data selection unit 12 for trajectory
generation selects positions located on a second direction side of
the determined position among the front side positions of the
target object, as the front side target object positions for
trajectory generation.
[0072] Herein, the first direction is an order of positions in
which the front side positions of the target object changes in the
front side, at least at the front side position of the target
object close to the position of the present own vehicle. In the
present embodiment, the first direction is an order chronologically
from the past to the present. Specifically, the first direction is
an order in which the number i of detection time point increases.
The second direction is an order of positions in which the front
side positions of the target object changes in the back side, at
least at the front side position of the target object close to the
position of the present own vehicle, and is an order of positions
opposite to the first direction. In the present embodiment, the
second direction is an order chronologically from the present to
the past. Specifically, the second direction is an order in which
the number i of detection time point decreases.
[0073] In the present embodiment, the data selection unit 12 for
trajectory generation determines the front side history positions
of the target object, which are located on the front side of the
present own vehicle, among the history positions of the plural time
points of the present and the past. The data selection unit 12 for
trajectory generation calculates the change direction of the
history positions between the numbers of detection time point in
the direction chronologically from the past to the present (the
first direction), about each of the front side history positions,
and determines a number where the absolute value of angle .alpha.f
of the change direction of the history positions with respect to
the front direction becomes greater than or equal to the
determination angle .alpha.j, among the front side history
positions. The data selection unit 12 for trajectory generation
selects the front side history positions of numbers older than the
determined number (the second direction side), as the front side
history positions for trajectory generation.
[0074] Processing of this front side can be configured as the
flowchart of FIG. 8. In the step S11, the data selection unit 12
for trajectory generation selects, as the front side history
positions, the history positions where the position Xfh.sub.i of
the front direction becomes greater than or equal to zero, among
the history positions (Xfh.sub.i, Yfh.sub.i) of the front object
corresponding to each number i (i= . . . , i.sub.0-2, i.sub.0-1,
i.sub.0) of detection time point of this time and the past. The
data selection unit 12 for trajectory generation sets the oldest
number Nfold of detection time point of front side, and the newest
number Nfnew of detection time point of front side, among the
numbers of detection time point selected as the front side history
positions.
[0075] In the step S12, the data selection unit 12 for trajectory
generation initializes a processing number L of detection time
point of front side, to the oldest number Nfold of detection time
point of front side (L=Nfold). Then, in the step S13, the data
selection unit 12 for trajectory generation determines whether or
not the processing number L of detection time point of front side
is smaller than the newest number Nfnew of detection time point of
front side (L<Nfnew); advances to the step S14 when determining
that it is smaller, and advances to the step S19 when determining
that it is not smaller.
[0076] In the step S14, the data selection unit 12 for trajectory
generation sets the history position (Xfh.sub.L, Yfh.sub.L) of the
front object corresponding to the processing number L of detection
time point of front side, as a reference position A.sub.L. In the
step S15, the data selection unit 12 for trajectory generation sets
the history position (Xfh.sub.L+1, Yfh.sub.L+1) of the front object
corresponding to the next number L+1 of detection time point of the
processing number L of detection time point of front side, as a
comparison position B.sub.L+1.
[0077] In the step S16, as shown in FIG. 9 and a next equation, the
data selection unit 12 for trajectory generation calculates an
angle .alpha.f of the direction from the reference position A.sub.L
(Xfh.sub.L, Yfh.sub.L) to the comparison position B.sub.L+1
(Xfh.sub.L+1, YfhL+1), with respect to the front direction (X-axis)
of the present own vehicle.
.alpha. .times. .times. f = tan - 1 .function. ( Yfh L + 1 - Yfh L
Xfh L + 1 - Xfh L ) ( 1 ) ##EQU00001##
[0078] In the step S17, the data selection unit 12 for trajectory
generation determines whether or not an absolute value of the angle
.alpha.f becomes greater than or equal to the determination angle
.alpha.j (|.alpha.f|>=aj); advances to the step S19 when
determining that it becomes greater than or equal to the
determination angle .alpha.j, and advances to the step S18 when
determining that it does not becomes greater than or equal to the
determination angle .alpha.j.
[0079] In the step S18, the data selection unit 12 for trajectory
generation increases the processing number L of detection time
point of front side by one (L=L+1); after that, advances to the
step S13 and executes again processing of the step S13 to the step
S17.
[0080] On the other hand, in the step S19, the data selection unit
12 for trajectory generation sets the currently set processing
number L of detection time point of front side, as a number Nfend
of detection time point of trajectory generation front end
(Nfend=L). Then, as shown in a next equation, the data selection
unit 12 for trajectory generation sets from the oldest number Nfold
of detection time point of front side to the number Nfend of
detection time point of trajectory generation front end, to a
trajectory generation range Nrngf of front side, and then ends the
processing.
Nrngf=Nfold.about.Nfend(=L) (2)
<Behavior of Front Side Processing>
[0081] A behavior of front side processing will be explained using
FIG. 10. From the processing number of detection time point L=Nfold
to Nfold+3, the absolute value of angle .alpha.f of the direction
from the history position (the reference position) corresponding to
this time processing number L of detection time point to the
history position (the comparison position) corresponding to the
next processing number L+1 of detection time point becomes smaller
than the determination angle .alpha.j which is set to 80 degrees,
for example. On the other hand, at the processing number of
detection time point L=Nfold+4, the absolute value of angle
.alpha.f of the direction from the history position (the reference
position) corresponding to this time processing number L=Nfold+4 of
detection time point to the history position (the comparison
position) corresponding to the next processing number L=Nfold+5 of
detection time point is larger than the determination angle
.alpha.j which is set to 80 degrees. Therefore, numbers at and
after the processing number of detection time point L=Nfold+5 when
the angle .alpha.f becomes large are not included in the trajectory
generation range of front side. And, the history positions from the
oldest number Nfold of detection time point of front side to the
processing number of detection time point L=Nfold+4 is set to the
trajectory generation range of front side.
<Processing of Back Side>
[0082] Next, processing of the backside will be explained. The data
selection unit 12 for trajectory generation determines back side
positions of the target object, which are located on back side of
the present own vehicle, among the plural positions of the target
object. The data selection unit 12 for trajectory generation
calculates a change direction of positions of the target object in
the second direction, about each of the back side positions of the
target object, and determines a position where an absolute value of
angle of the change direction of positions of the target object
with respect to the back direction becomes greater than or equal to
the determination angle .alpha.j, among the back side positions of
the target object. The data selection unit 12 for trajectory
generation selects positions located on the first direction side of
the determined position among the back side positions of the target
object, as the back side target object positions for trajectory
generation.
[0083] In the present embodiment, the data selection unit 12 for
trajectory generation determines the back side history positions of
the target object, which are located on back side of the present
own vehicle, among the history positions of the plural time points
of the present and the past. The data selection unit 12 for
trajectory generation calculates the change direction of the
history positions between the numbers of detection time point in
the direction chronologically from the present to the past (the
second direction), about each of the back side history positions,
and determines a number where the absolute value of angle .alpha.r
of the change direction of the history positions with respect to
the back direction becomes less than or equal to the determination
angle .alpha.j, among the back side history positions. The data
selection unit 12 for trajectory generation selects the back side
history positions of numbers newer than the determined number (the
first direction side), as the back side history positions for
trajectory generation.
[0084] Processing of this back side can be configured as the
flowchart of FIG. 11. In the step S21, the data selection unit 12
for trajectory generation selects, as the back side history
positions, the history positions where the position Xfh.sub.i of
the front direction becomes less than or equal to zero, among the
history positions (Xfh.sub.i, Yfh.sub.i) of the front object
corresponding to each number i (i= . . . , i.sub.0-2, i.sub.0-1,
i.sub.0) of detection time point of this time and the past. The
data selection unit 12 for trajectory generation sets the oldest
number Nrold of detection time point of back side, and the newest
number Nrnew of detection time point of back side, among the
numbers of detection time point selected as the back side history
positions.
[0085] In the step S22, the data selection unit 12 for trajectory
generation initializes a processing number M of detection time
point of back side, to the newest number Nrnew of detection time
point of back side (M=Nrnew). Then, in the step S23, the data
selection unit 12 for trajectory generation determines whether or
not the processing number M of detection time point of back side is
greater than the oldest number Nrold of detection time point of
back side (M>Nrold); advances to the step S24 when determining
that it is greater, and advances to the step S29 when determining
that it is not greater.
[0086] In the step S24, the data selection unit 12 for trajectory
generation sets the history position (Xfh.sub.M, Yfh.sub.M) of the
front object corresponding to the processing number M of detection
time point of back side, as a reference position C.sub.M. In the
step S25, the data selection unit 12 for trajectory generation sets
the history position (Xfh.sub.M-1, Yfh.sub.M-1) of the front object
corresponding to the previous number M-1 of detection time point of
the processing number M of detection time point of back side, as a
comparison position D.sub.M-1.
[0087] In the step S26, as shown in FIG. 12 and a next equation,
the data selection unit 12 for trajectory generation calculates an
angle .alpha.r of the direction from the reference position C.sub.M
(Xfh.sub.M, Yfh.sub.M) to the comparison position D.sub.M-1
(Xfh.sub.M-1, Yfh.sub.M-1), with respect to the back direction of
the present own vehicle.
.alpha. .times. .times. r = tan - 1 .function. ( Yfh M - Yfh M - 1
Xfh M - 1 - Xfh M ) ( 3 ) ##EQU00002##
[0088] In the step S27, the data selection unit 12 for trajectory
generation determines whether or not an absolute value of the angle
.alpha.r becomes greater than or equal to the determination angle
.alpha.j (|.alpha.r|>=.alpha.j); advances to the step S29 when
determining that it becomes greater than or equal to the
determination angle .alpha.j, and advances to the step S28 when
determining that it does not becomes greater than or equal to the
determination angle .alpha.j.
[0089] In the step S28, the data selection unit 12 for trajectory
generation decreases the processing number M of detection time
point of back side by one (M=M-1); after that, advances to the step
S23 and executes again processing of the step S23 to the step
S27.
[0090] On the other hand, in the step S29, the data selection unit
12 for trajectory generation sets the currently set processing
number M of detection time point of back side, as a number Nrend of
detection time point of trajectory generation back end (Nrend=M).
Then, as shown in a next equation, the data selection unit 12 for
trajectory generation sets from the number Nrend of detection time
point of trajectory generation back end to the newest number Nrnew
of detection time point of back side, to a trajectory generation
range Nrngr of back side, and then ends the processing.
Nrngr=Nrend(=M).about.Nrnew (4)
<Behavior of Back Side Processing>
[0091] A behavior of back side processing will be explained using
FIG. 13. From the processing number of detection time point M=Nrnew
to Nrnew-2, the absolute value of angle .alpha.r of the direction
from the history position (the reference position) corresponding to
this time processing number M of detection time point to the
history position (the comparison position) corresponding to the
previous processing number M-1 of detection time point becomes
smaller than the determination angle .alpha.j which is set to 80
degrees, for example. Since the next processing number of detection
time point M=Nrnew-3 is the oldest number Nrold of detection time
point of back side, the selection processing is ended. And, the
history positions from the newest number Nrnew of detection time
point of back side to the oldest number Nrold of detection time
point of back side is set to the trajectory generation range of
back side.
<Total of Trajectory Generation Range of Front Side and Back
Side>
[0092] The data selection unit 12 for trajectory generation totals
the history positions for trajectory generation of front side, and
the history positions for the trajectory generation of backside,
and sets the history position for trajectory generation. In the
present embodiment, as shown in a next equation, the data selection
unit 12 for trajectory generation combines the trajectory
generation range Nrngf of front side, and the trajectory generation
range Nrngr of backside, and sets from the number Nfend of
detection time point of trajectory generation front end to the
number Nrend of detection time point of trajectory generation back
end, to the trajectory generation range Nrng. Then, the data
selection unit 12 for trajectory generation selects the history
positions corresponding to the trajectory generation range Nrng, as
the history positions for trajectory generation.
Nrng=Nrngf+Nrngr=Nrend.about.Nfend (5)
1-3. Trajectory Generation Unit 13
[0093] In the step S05 of FIG. 3, the trajectory generation unit 13
performs a trajectory generation processing (a trajectory
generation step) that generates a trajectory of the target object
(in this example, the front object) based on the target object
positions for trajectory generation (in this example, the history
positions).
[0094] In the present embodiment, the trajectory generation unit 13
generates the trajectory on the own vehicle coordinate system which
is based on the position of the present own vehicle. As shown in a
next equation, the trajectory generation unit 13 generates the
trajectory by approximation using a polynomial in which a value X
of the coordinate axis of front direction is input variable, and a
value Y of the coordinate axis of lateral direction is output
variable. The trajectory generation unit 13 limits the trajectory
generated using the polynomial within the trajectory generation
range.
Y=a.sub.hmxX.sup.hmx+a.sub.hmx-1X.sup.hmx-1+ . . .
+a.sub.1X.sup.1+a.sub.0
Xf.sub.Nrend.ltoreq.X.ltoreq.Xf.sub.Nfend (6)
[0095] Herein, hmx is the maximum order of the polynomial and is
preliminarily set. a.sub.hmx, a.sub.hmx-1, . . . , a.sub.1, a.sub.0
are coefficients of respective orders hmx, hmx-1, . . . , 1, 0.
Xf.sub.Nrend is a value of the coordinate axis of front direction
of the history position at the number Nrend of detection time point
of trajectory generation back end in the trajectory generation
range. Xf.sub.Nfend is a value of the coordinate axis of front
direction of the history position at the number Nfend of detection
time point of trajectory generation front end in the trajectory
generation range. The trajectory generation unit 13 adjusts each
order coefficient a using the least square method and the like so
that error between the history positions for trajectory generation
and the polynomial becomes small.
[0096] FIG. 14 illustrates a comparative example that is different
from the present embodiment. In the comparative example, the range
where the absolute value of angle .alpha.f becomes larger than
determination angle .alpha.j is also set to the trajectory
generation range of front side. Therefore, in the trajectory
generation, since approximation is performed including the part
where the change angle of the history positions become large,
approximate precision is deteriorated. Although improvement in
approximate precision is expected if order of the polynomial is
increased, it is necessary to increase the number of the history
positions for trajectory generation by the increase of order, and
is not desirable. If the change angle of the history positions is
greater than or equal to 90 degrees like the example of FIG. 14,
plural history positions where values of the lateral direction
(Y-axis) are different with respect to values of the similar front
direction (X-axis) occur. Therefore, the approximate error becomes
large if approximation using the polynomial in which the value of
the front direction (X-axis) is the input variable is performed. On
the other hand, in the present embodiment, as shown in FIG. 15,
since the part where the change angle of history positions becomes
large is removed, the approximate precision of the trajectory
becomes high.
1-6. Steering Control Unit 14
[0097] In the step S04 of FIG. 3, the steering control unit 14
performs a steering control processing (a steering control step)
that performs a trajectory tracking steering control which controls
the steering angle of the own vehicle so that the own vehicle
follows the trajectory.
[0098] In the present embodiment, as shown in FIG. 16, the steering
control unit 14 sets a position of the trajectory which is located
ahead by a front gaze distance Xw from the position of the present
own vehicle, to a target position Yt of the lateral direction of
the own vehicle, and controls the steering angle so that a position
of the lateral direction of the own vehicle approaches the target
position Yt. Specifically, as shown in a next equation, the
steering control unit 14 inputs the front gaze distance Xw into the
value X of the coordinate axis of front direction of the equation
(6), and sets the calculated value Y of the coordinate axis of
lateral direction to the target position Yt.
Yt=a.sub.hmxXw.sup.hmx+a.sub.hmx-1Xw.sup.hmx-1+ . . .
+a.sub.1Xw.sup.1+a.sub.0 (7)
[0099] The steering control unit 14 sets a command value of
steering angle according to the target position Yt. Since the
position of the lateral direction of the present own vehicle is
Y=0, the steering control unit 14 sets an angle of left direction
according to the target position Yt, to the command value of the
steering angle, when the target position Yt is a positive value,
and sets an angle of right direction according to the target
position Yt, to the command value of steering angle, when the
target position Yt is a negative value.
[0100] The steering control unit 14 transmits the command value of
steering angle to the steering apparatus 24 via the communication
device and the like. The steering apparatus 24 is configured by an
electric power steering apparatus, and it performs driving control
of an electric motor for steering so that the steering angle of
wheels coincide with the command value of steering angle.
[0101] The steering control unit 14 sets the front gaze distance Xw
according to the front endpoint Xf.sub.Nfend of the trajectory. The
steering control unit 14 sets the front gaze distance Xw to a
distance shorter than front endpoint Xf.sub.Nfend of the
trajectory. The front endpoint Xf.sub.Nfend of the trajectory
becomes the value Xf.sub.Nfend of the front direction of the
history position of the front end of the trajectory generation
range.
[0102] According to this configuration, in accordance with change
of the front end of the trajectory generation range, the front gaze
distance Xw can be set appropriately in the trajectory generation
range.
[0103] In the present embodiment, by referring to a map data in
which a relationship between the front endpoint Xf.sub.Nfend of the
trajectory and the front gaze distance Xw is preliminarily set, the
steering control unit 14 calculates the front gaze distance Xw
corresponding to the front endpoint Xf.sub.Nfend of the present
trajectory.
[0104] As an example of setting of the map data is shown in FIG.
17, in a range where the front endpoint Xf.sub.Nfend of the
trajectory is larger than an upper limit value X1, the front gaze
distance Xw is set to a fixed value X2 smaller than the upper limit
value X1. In a range where the front endpoint Xf.sub.Nfend of the
trajectory is smaller than the upper limit value X1, as the front
endpoint Xf.sub.Nfend of the trajectory decreases, the front gaze
distance Xw is decreased and is set smaller than the front endpoint
Xf.sub.Nfend of the trajectory.
[0105] According to this configuration, in the range where front
endpoint Xf.sub.Nfend of the trajectory is larger than the upper
limit value X1, the front gaze distance Xw is set to the fixed
value X2, and the front gaze distance Xw can be prevented from
separating too much in front, and can be set to an appropriate
distance for the trajectory tracking steering control. On the other
hand, as the front endpoint Xf.sub.Nfend of the trajectory
decreases less than the upper limit value X1, the front gaze
distance Xw can be decreased and the front gaze distance Xw can be
set in the trajectory generation range.
[0106] In the present embodiment, the steering control unit 14
performs the trajectory tracking steering control when the front
endpoint Xf.sub.Nfend of the trajectory is greater than or equal to
the lower limit value X3, and does not perform the trajectory
tracking steering control when the front endpoint Xf.sub.Nfend of
the trajectory is smaller than the lower limit value X3. Therefore,
in the map data of FIG. 17, the front gaze distance Xw is not set
in the range where the front endpoint Xf.sub.Nfend of the
trajectory is smaller than the lower limit value X3.
[0107] According to this configuration, when the front endpoint
Xf.sub.Nfend of the trajectory is too close to the own vehicle and
the appropriate front gaze distance Xw cannot be set, the
trajectory tracking steering control can be prevented from
performing.
[0108] And, in the present embodiment, the steering control unit 14
performs the trajectory tracking steering control when the number
of the history positions for trajectory generation is greater than
or equal to the maximum order of the polynomial hmx+1, and does not
perform the trajectory tracking steering control when the number of
the history positions for trajectory generation is smaller than the
maximum order hmx+1.
[0109] For the determination of the coefficients of the polynomial,
the number of the history positions for trajectory generation
greater than or equal to the maximum order of the polynomial hmx+1
is necessary. According to the above configuration, when the number
of the history positions for trajectory generation is smaller than
the maximum order of the polynomial hmx+1, the trajectory tracking
steering control using the trajectory generated by the polynomial
with low approximate precision can be prevented from
performing.
2. Embodiment 2
[0110] The vehicle position processing apparatus 10 according to
Embodiment 2 will be explained. The explanation for constituent
parts the same as those in Embodiment 1 will be omitted. The basic
configuration of the vehicle position processing apparatus 10
according to the present embodiment is the same as that of
Embodiment 1. Embodiment 2 is different from Embodiment 1 in
processing of the data selection unit 12 for trajectory
generation.
[0111] In the present embodiment, as similar to Embodiment 1, the
data selection unit 12 for trajectory generation sets the
trajectory generation range to a continuous range, which includes
position of the target object close to a position of front and back
direction of the present own vehicle and in which an absolute value
of angle of change direction of position of the target object with
respect to the front and back direction of the present own vehicle
becomes smaller than the determination angle .alpha.j.
[0112] However, in the present embodiment, the determination angle
.alpha.j is set to .pi./2 (90 degrees), and detailed processing of
the data selection unit 12 for trajectory generation is different
from Embodiment 1.
[0113] Also in the present embodiment, the data selection unit 12
for trajectory generation divides the history positions of plural
time points into front side and back side of the position of the
present own vehicle, and selects the history positions for
trajectory generation about each of the front side history
positions and the back side history positions.
<Processing of Front Side>
[0114] Processing of the front side will be explained. The data
selection unit 12 for trajectory generation determines front side
positions of the target object, which are located on the front side
of the present own vehicle, among the plural positions of the
target object. The data selection unit 12 for trajectory generation
determines a position where the positions of the target object
changes in the back direction in the first direction, among the
front side positions of the target object. The data selection unit
12 for trajectory generation selects positions located on the
second direction side of the determined position among the front
side positions of the target object, as the front side target
object positions for trajectory generation.
[0115] Herein, as similar to Embodiment 1, the first direction is
an order of positions in which the front side positions of the
target object changes in the front side, at least at the front side
position of the target object close to the position of the present
own vehicle. In the present embodiment, the first direction is an
order chronologically from the past to the present. Specifically,
the first direction is an order in which the number i of detection
time point increases. The second direction is an order of positions
in which the front side positions of the target object changes in
the back side, at least at the front side position of the target
object close to the position of the present own vehicle, and is an
order of positions opposite to the first direction. In the present
embodiment, the second direction is an order chronologically from
the present to the past. Specifically, the second direction is an
order in which the number i of detection time point decreases.
[0116] In the present embodiment, the data selection unit 12 for
trajectory generation determines the front side history positions
of the target object, which are located on the front side of the
present own vehicle, among the history positions of the plural time
points of the present and the past. The data selection unit 12 for
trajectory generation determines a number where the history
positions change in the back direction between the numbers of
detection time point in the direction chronologically from the past
to the present (the first direction), among the history positions
of front side. The data selection unit 12 for trajectory generation
selects the front side history positions of numbers older than the
determined number (the second direction side), as the front side
history positions for trajectory generation. This time point when
the history positions changes in the back direction is a time point
when the absolute value of angle of change direction of the history
positions with respect to the front and back direction of the own
vehicle becomes larger than the determination angle .alpha.j which
is set to .pi./2.
[0117] Processing of this front side can be configured as the
flowchart of FIG. 18. In the step S31, the data selection unit 12
for trajectory generation selects, as the front side history
positions, the history positions where the position Xfh.sub.i of
the front direction becomes greater than or equal to zero, among
the history positions (Xfh.sub.i, Yfh.sub.i) of the front object
corresponding to each number i (i= . . . , i.sub.0-2, i.sub.0-1,
i.sub.0) of detection time point of this time and the past. The
data selection unit 12 for trajectory generation sets the oldest
number Nfold of detection time point of front side, and the newest
number Nfnew of detection time point of front side, among the
numbers of detection time point selected as the front side history
positions.
[0118] In the step S32, the data selection unit 12 for trajectory
generation initializes a processing number L of detection time
point of front side, to the oldest number Nfold of detection time
point of front side (L=Nfold). Then, in the step S33, the data
selection unit 12 for trajectory generation determines whether or
not the processing number L of detection time point of front side
is smaller than the newest number Nfnew of detection time point of
front side (L<Nfnew); advances to the step S34 when determining
that it is smaller, and advances to the step S38 when determining
that it is not smaller.
[0119] In the step S34, the data selection unit 12 for trajectory
generation sets the history position (Xfh.sub.L, Yfh.sub.L) of the
front object corresponding to the processing number L of detection
time point of front side, as a reference position A.sub.L. In the
step S35, the data selection unit 12 for trajectory generation sets
the history position (Xfh.sub.L+1, Yfh.sub.L+1) of the front object
corresponding to the next number L+1 of detection time point of the
processing number L of detection time point of front side, as a
comparison position B.sub.L+1.
[0120] In the step S36, the data selection unit 12 for trajectory
generation determines whether or not the position Xfh.sub.L+1 of
the front direction of the comparison position B.sub.L+1 becomes
less than or equal to the position Xfh.sub.L of the front direction
of the reference position A.sub.L (Xfh.sub.L+1<=Xfh.sub.L);
advances to the step S38 when determining that it becomes less than
or equal to the position Xfh.sub.L, and advances to the step S37
when determining that it does not become less than or equal to the
position Xfh.sub.L.
[0121] In the step S37, the data selection unit 12 for trajectory
generation increases the processing number L of detection time
point of front side by one (L=L+1); after that, advances to the
step S33 and executes again processing of the step S33 to the step
S36.
[0122] On the other hand, in the step S38, the data selection unit
12 for trajectory generation sets the currently set processing
number L of detection time point of front side, as a number Nfend
of detection time point of trajectory generation front end
(Nfend=L). Then, as shown in the equation (2), the data selection
unit 12 for trajectory generation sets from the oldest number Nfold
of detection time point of front side to the number Nfend of
detection time point of trajectory generation front end, to a
trajectory generation range Nrngf of front side, and then ends the
processing.
<Behavior of Front Side Processing>
[0123] A behavior of front side processing will be explained using
FIG. 19. From the processing number of detection time point L=Nfold
to Nfold+3, the position Xfh.sub.L of the front direction of the
history position (the reference position) corresponding to this
time processing number L of detection time point becomes smaller
than the position Xfh.sub.L+1 of the front direction of the history
position (the comparison position) corresponding to the next
processing number L+1 of detection time point. On the other hand,
at the processing number of detection time point L=Nfold+4, the
position Xfh.sub.Nfold+4 of the front direction of the history
position (the reference position) corresponding to this time
processing number L=Nfold+4 of detection time point becomes greater
than or equal to the position Xfh.sub.Nfold+5 of the front
direction of the history position (the comparison position)
corresponding to the next processing number L=Nfold+5 of detection
time point. Therefore, numbers at and after the processing number
of detection time point L=Nfold+5 are not included in the
trajectory generation range of front side. And, the history
positions from the oldest number Nfold of detection time point of
front side to the processing number of detection time point
L=Nfold+4 is set as the trajectory generation range of front side.
According to this selection, as explained using the comparative
example of FIG. 14, and FIG. 15 in Embodiment 1, the approximate
precision of the trajectory becomes high.
<Processing of Back Side>
[0124] Next, processing of the backside will be explained. The data
selection unit 12 for trajectory generation determines back side
positions of the target object, which are located on back side of
the present own vehicle, among the plural positions of the target
object. The data selection unit 12 for trajectory generation
determines a position where the positions of the target object
changes in the front direction in the second direction, among the
back side positions of the target object. The data selection unit
12 for trajectory generation selects positions located on the first
direction side of the determined position among the back side
positions of the target object, as the back side target object
positions for trajectory generation.
[0125] In the present embodiment, the data selection unit 12 for
trajectory generation determines the back side history positions of
the target object, which are located on back side of the present
own vehicle, among the history positions of the plural time points
of the present and the past. The data selection unit 12 for
trajectory generation determines a number where the history
positions change in the front direction between the numbers of
detection time point in the direction chronologically from the
present to the past (the second direction), among the history
positions of back side. The data selection unit 12 for trajectory
generation selects the back side history positions of numbers newer
than the determined number (the first direction side), as the back
side history positions for trajectory generation. This time point
when the history positions changes in the front direction is a time
point when the absolute value of angle of change direction of the
history positions with respect to the front and back direction of
the own vehicle becomes larger than the determination angle
.alpha.j which is set to .pi./2.
[0126] Processing of this back side can be configured as the
flowchart of FIG. 20. In the step S41, the data selection unit 12
for trajectory generation selects, as the back side history
positions, the history positions where the position Xfh.sub.i of
the front direction becomes less than or equal to zero, among the
history positions (Xfh.sub.i, Yfh.sub.i) of the front object
corresponding to each number i (i= . . . , i.sub.0-2, i.sub.0-1,
i.sub.0) of detection time point of this time and the past. The
data selection unit 12 for trajectory generation sets the oldest
number Nrold of detection time point of back side, and the newest
number Nrnew of detection time point of back side, among the
numbers of detection time point selected as the back side history
positions.
[0127] In the step S42, the data selection unit 12 for trajectory
generation initializes a processing number M of detection time
point of back side, to the newest number Nrnew of detection time
point of back side (M=Nrnew). Then, in the step S43, the data
selection unit 12 for trajectory generation determines whether or
not the processing number M of detection time point of back side is
greater than the oldest number Nrold of detection time point of
back side (M>Nrold); advances to the step S44 when determining
that it is greater, and advances to the step S48 when determining
that it is not greater.
[0128] In the step S44, the data selection unit 12 for trajectory
generation sets the history position (Xfh.sub.M, Yfh.sub.M) of the
front object corresponding to the processing number M of detection
time point of back side, as a reference position C.sub.M. In the
step S45, the data selection unit 12 for trajectory generation sets
the history position (Xfh.sub.M-1, Yfh.sub.M-1) of the front object
corresponding to the previous number M-1 of detection time point of
the processing number M of detection time point of back side, as a
comparison position D.sub.M-1.
[0129] In the step S46, as shown in FIG. 20, the data selection
unit 12 for trajectory generation determines whether or not the
position Xfh.sub.M-1 of the front direction of the comparison
position D.sub.M-1 becomes greater than or equal to the position
Xfh.sub.M of the front direction of the reference position C.sub.M
(Xfh.sub.M-1>=Xfh.sub.M); advances to the step S48 when
determining that it becomes greater than or equal to the position
Xfh.sub.M, and advances to the step S47 when determining that it
does not become greater than or equal to the position
Xfh.sub.M.
[0130] In the step S47, the data selection unit 12 for trajectory
generation decreases the processing number M of detection time
point of back side by one (M=M-1); after that, advances to the step
S43 and executes again processing of the step S43 to the step
S46.
[0131] On the other hand, in the step S48, the data selection unit
12 for trajectory generation sets the currently set processing
number M of detection time point of back side, as a number Nrend of
detection time point of trajectory generation back end (Nrend=M).
Then, as shown in the equation (4), the data selection unit 12 for
trajectory generation sets from the number Nrend of detection time
point of trajectory generation back end to the newest number Nrnew
of detection time point of back side, as a trajectory generation
range Nrngr of back side, and then ends the processing.
<Behavior of Back Side Processing>
[0132] A behavior of back side processing will be explained using
FIG. 21. From the processing number of detection time point M=Nrnew
to Nrnew-2, the position Xfh.sub.M of the front direction of the
history position (the reference position) corresponding to this
time processing number M of detection time point becomes greater
than the position Xfh.sub.M-1 of the front direction of the history
position (the comparison position) corresponding to the previous
processing number M-1 of detection time point. Since the next
processing number of detection time point M=Nrnew-3 is the oldest
number Nrold of detection time point of back side, the selection
processing is ended. And, the history positions from the newest
number Nrnew of detection time point of back side to the oldest
number Nrold of detection time point of back side is set as the
trajectory generation range of back side.
<Total of Trajectory Generation Range of Front Side and Back
Side>
[0133] The data selection unit 12 for trajectory generation totals
the history positions for trajectory generation of front side, and
the history positions for the trajectory generation of backside,
and sets the history position for trajectory generation. In the
present embodiment, as shown in the equation (5), the data
selection unit 12 for trajectory generation combines the trajectory
generation range Nrngf of front side, and the trajectory generation
range Nrngr of backside, and sets from the number Nfend of
detection time point of trajectory generation front end to the
number Nrend of detection time point of trajectory generation back
end, as the trajectory generation range Nrng. The data selection
unit 12 for trajectory generation selects the history positions
corresponding to the trajectory generation range Nrng, as the
history positions for trajectory generation.
3. Embodiment 3
[0134] The vehicle position processing apparatus 10 according to
Embodiment 3 will be explained. The explanation for constituent
parts the same as those in each of Embodiments 1 or 2 will be
omitted. The basic configuration of the vehicle position processing
apparatus 10 according to the present embodiment is the same as
that of Embodiment 1 or 2. Embodiment 3 is different from
Embodiment 1 or 2 in processing of the target object position
acquisition unit 11.
[0135] Also in the present embodiment, the target object position
acquisition unit 11 obtains positions of the target object.
However, in the present embodiment, as shown in FIG. 23, the target
object is a road point obtained from map data. The plural positions
of the target object are positions of plural road points arranged
in order along a traveling direction of a road where the own
vehicle travels. Also in the present embodiment, the position of
the road point is managed by the number. And, as the number i of
order, the number of order along the traveling direction of the
road is set. As shown in FIG. 22, the target object position
acquisition unit 11 is provided with an own position information
acquisition unit 11a and a road position acquisition unit 11d.
[0136] The own position information acquisition unit 11a obtains
position of the present own vehicle. In the present embodiment, the
own position information acquisition unit 11a obtains the position
of the present own vehicle based on the output signal of the own
position detecting device 21, for every detection period.
[0137] The own position detecting device 21 is a device which
detects the position information of the own vehicle. As the own
position detecting device 21, for example, one or more of various
kinds of detecting devices, such as a GPS (Global Positioning
System) receiver, and a beacon receiver are used. The own position
detecting device 21 may be provided in the vehicle position
processing apparatus 10, or may be provided in the external
apparatus of the vehicle position processing apparatuses 10, such
as a car navigation apparatus, and data may be obtained via the
communication device. Although the detection position of the own
vehicle by the GPS receiver may be used as it is when the high
precision GPS is used, the position of the own vehicle specified by
map matching may be used.
[0138] As shown in FIG. 23, for every detection period, the road
position acquisition unit 11d obtains, as the plural positions of
the target object, positions of plural road points arranged in
order along the traveling direction of the road where the own
vehicle travels, from the map data 11e, based on the position of
the present own vehicle. The road position acquisition unit 11d
sets, as the number i of order, the number of order along the
traveling direction of the road. The position of road point is set
to the position of the central part in the cross direction of the
road where the own vehicle is traveling or the traveling lane.
[0139] In the present embodiment, as shown in FIG. 23, the road
position acquisition unit 11d obtains not only the positions of the
road points on the front side of the position of the present own
vehicle, but also the positions of the road points on the back side
of the position of the present own vehicle, along the traveling
direction of the road. Then, for every detection period, the road
position acquisition unit 11d sets the number i of road point which
increases from back to front in order, for each of the obtained
positions of plural road points.
[0140] In the map data, road information, such as position
information on each point of the road (latitude, longitude,
altitude), is stored. The map data may be stored in the storage
apparatus 91 such as the flash memory of the vehicle position
processing apparatus 10, or may be stored in the storage apparatus
of the external apparatus, such as the car navigation apparatus,
and data may be obtained via the communication device. When the
route guide is performed by the navigation function, the position
of the road point along the traveling direction of the guide route
may be obtained.
[0141] For every detection period, the road position acquisition
unit 11d calculates relative position coordinates of the plural
road points on the basis of the position of the present own vehicle
on the own vehicle coordinate system, by performing coordinate
conversion to the obtained positions of the plural road points.
[0142] The data selection unit 12 for trajectory generation sets
the trajectory generation range which is a range of continuous
numbers of road point including the number of the position of the
road point close to the position of the front and back direction of
the present own vehicle, and selects positions of the road points
included in the trajectory generation range among the positions of
the plural road points, as the target object positions for
trajectory generation.
[0143] The data selection unit 12 for trajectory generation sets
the trajectory generation range to a range of continuous numbers of
order which include the number of the position of the road point
close to the position of the front and back direction of the
present own vehicle and in which an absolute value of angle as of
change direction of the positions of the road points between the
numbers of road point with respect to the front and back direction
of the present own vehicle becomes smaller than the determination
angle .alpha.j.
[0144] According to this configuration, inclination as of the
change direction of the positions of the road points with respect
to the front and back direction of the present own vehicle can be
made smaller than the determination angle .alpha.j continuously to
the front and back direction from the position of the front and
back direction of the present own vehicle. If the inclination as of
the change direction of the positions of the road points becomes
large too much, there is a possibility that the approximate
precision of the trajectory may be deteriorated. Therefore, by
excluding the positions of the road points where the inclination
becomes larger than the determination angle .alpha.j, it is
possible to suppress deterioration of the approximate precision of
the trajectory. In the case of performing the trajectory tracking
steering control which makes the own vehicle follow the trajectory,
when the inclination of the trajectory becomes large too much,
tracking of the own vehicle becomes not easy. Therefore, by
excluding the positions of the road points where the inclination as
becomes larger than the determination angle .alpha.j, the
trajectory the own vehicle can follow can be generated.
<When it is Configured Similar to Embodiment 1>
[0145] When it is configured similar to Embodiment 1, the data
selection unit 12 for trajectory generation determines front side
positions of the road points, which are located on the front side
of the present own vehicle, among the positions of the plural road
points. The data selection unit 12 for trajectory generation
calculates the change direction of the positions of the road points
between the numbers of order in the first direction, about each of
the front side positions of the road points, and determines a
position where the absolute value of angle of the change direction
of the positions of the road points with respect to the front
direction becomes greater than or equal to the determination angle
.alpha.j, among the front side positions of the road points. The
data selection unit 12 for trajectory generation selects the front
side positions of the road points of numbers on the second
direction side of the determined number, as the front side
positions of the road points for trajectory generation.
[0146] Herein, the first direction is an order from the back to the
front along the traveling direction of the road. Specifically, the
first direction is an order in which the number i of road point
increases. The second direction is an order from the front to the
back along the traveling direction of the road. Specifically, the
second direction is an order in which the number i of road point
decreases.
[0147] The data selection unit 12 for trajectory generation
determines back side positions of the road points, which are
located on the back side of the present own vehicle, among the
positions of the plural road points. The data selection unit 12 for
trajectory generation calculates the change direction of the
positions of the road points between the numbers of order in the
second direction, about each of the back side positions of the road
points, and determines a position where the absolute value of angle
of the change direction of the positions of the road points with
respect to the back direction becomes greater than or equal to the
determination angle .alpha.j, among the back side positions of the
road points. The data selection unit 12 for trajectory generation
selects the back side positions of the road points of numbers on
the first direction side of the determined number, as the back side
positions of the road points for trajectory generation.
[0148] In this case, by replacing the number i of detection time
point in Embodiment 1 to the number i of road point and replacing
the history positions in Embodiment 1 to the positions of the road
points, it is configured similar to the processing explained using
the flowchart of FIG. 8, and the flowchart of FIG. 11. Therefore,
explanation is omitted.
<When it is Configured Similar to Embodiment 2>
[0149] When it is configured similar to Embodiment 2, the data
selection unit 12 for trajectory generation determines front side
positions of the road points, which are located on the front side
of the present own vehicle, among the positions of the plural road
points. The data selection unit 12 for trajectory generation
determines a number where the positions of the road points changes
in the back direction between the numbers of order in the first
direction, among the front side positions of the road points. The
data selection unit 12 for trajectory generation selects the front
side positions of the road points of numbers on the second
direction side of the determined number, as the front side
positions of the road points for trajectory generation.
[0150] Herein, similarly, the first direction is an order from the
back to the front along the traveling direction of the road.
Specifically, the first direction is an order in which the number i
of road point increases. The second direction is an order from the
front to the back along the traveling direction of the road.
Specifically, the second direction is an order in which the number
i of road point decreases.
[0151] The data selection unit 12 for trajectory generation
determines back side positions of the road points, which are
located on the back side of the present own vehicle, among the
positions of the plural road points. The data selection unit 12 for
trajectory generation determines a number where the positions of
the road points changes in the front direction between the numbers
of order in the second direction, among the back side positions of
the road points. The data selection unit 12 for trajectory
generation selects the back side positions of the road points of
numbers on the first direction side of the determined number, as
the back side positions of the road points for trajectory
generation.
[0152] In this case, by replacing the number i of detection time
point in Embodiment 2 to the number i of road point and replacing
the history positions in Embodiment 2 to the positions of the road
points, it is configured similar to the processing explained using
the flowchart of FIG. 18, and the flowchart of FIG. 20. Therefore,
explanation is omitted.
Other Embodiments
[0153] Lastly, other embodiments of the present disclosure will be
explained. Each of the configurations of embodiments to be
explained below is not limited to be separately utilized but can be
utilized in combination with the configurations of other
embodiments as long as no discrepancy occurs.
[0154] (1) In each of the above-mentioned Embodiments, there has
been explained the case where the vehicle position processing
apparatus 10 is provided with the steering control unit 14.
However, embodiments of the present disclosure are not limited to
the foregoing case. That is to say, the vehicle position processing
apparatus 10 may not be provided with the steering control unit 14,
but may be provided with from the target object position
acquisition unit 11 to the trajectory generation unit 13. In this
case, the vehicle position processing apparatus 10 can also be
called a trajectory generating apparatus. If the vehicle position
processing apparatus 10 is provided with the steering control unit
14 as each Embodiment, the vehicle position processing apparatus 10
is also called as a vehicle control apparatus.
[0155] (2) In Embodiments 1, 2, there has been explained the case
where the front body detecting device 20 detects the preceding
vehicle which exists in front of the own vehicle, and detects the
relative position of the preceding vehicle with respect to the own
vehicle. However, embodiments of the present disclosure are not
limited to the foregoing case. That is to say, the front body
detecting device 20 may detect a body other than the preceding
vehicle which exists in front of the own vehicle, as the front
object. For example, the front body detecting device 20 may detect
the relative value position of the preceding vehicle which is
traveling the lane adjacent to the traveling lane of the own
vehicle, and may generate the trajectory of the preceding vehicle
of the adjacent lane. In this case, the trajectory tracking
steering control may not be performed, but a control for prevention
safety may be performed.
[0156] (3) In each of the above-mentioned Embodiments, there has
been explained the case where the data selection unit 12 for
trajectory generation selects the back side target object positions
for trajectory generation in addition to the front side target
object positions for trajectory generation. However, embodiments of
the present disclosure are not limited to the foregoing case. That
is to say, the data selection unit 12 for trajectory generation may
select only the front side target object positions for trajectory
generation, and may not select the back side target object
positions for trajectory generation. And, the trajectory generation
unit 13 may generate the trajectory of the target object based on
only the front side target object positions for trajectory
generation.
[0157] Although the present disclosure is described above in terms
of various exemplary embodiments and implementations, it should be
understood that the various features, aspects and functionality
described in one or more of the individual embodiments are not
limited in their applicability to the particular embodiment with
which they are described, but instead can be applied, alone or in
various combinations to one or more of the embodiments. It is
therefore understood that numerous modifications which have not
been exemplified can be devised without departing from the scope of
the present application. For example, at least one of the
constituent components may be modified, added, or eliminated. At
least one of the constituent components mentioned in at least one
of the preferred embodiments may be selected and combined with the
constituent components mentioned in another preferred
embodiment.
REFERENCE SIGNS LIST
[0158] 10 Vehicle Position Processing Apparatus (Vehicle Control
Apparatus), 11 Target Object Position Acquisition Unit, 11a Own
position information acquisition unit, 11b Front object position
acquisition unit, 11c History position calculation unit, 11d Road
position acquisition unit, 12 Data Selection Unit for Trajectory
Generation, 13 Trajectory Generation Unit, 14 Steering Control
Unit, .alpha.j Determination angle
* * * * *